Clermont Université, Université Blaise Pascal, UMRA 547 PIAF, F-63177 Aubière, France.
Tree Physiol. 2010 Dec;30(12):1586-98. doi: 10.1093/treephys/tpq088. Epub 2010 Oct 26.
Hevea brasiliensis is an important industrial crop for natural rubber production. Latex biosynthesis occurs in the cytoplasm of highly specialized latex cells and requires sucrose as the unique precursor. Ethylene stimulation of latex production results in high sugar flow from the surrounding cells of inner bark towards the latex cells. The aim of this work was to understand the role of seven sucrose transporters (HbSUTs) and one hexose transporter (HbHXT1) in this process. Two Hevea clones were used: PB217 and PB260, respectively described as high and low yielding clones. The expression pattern of these sugar transporters (HbSUTs and HbHXT1) was monitored under different physiological conditions and found to be maximal in latex cells. HbSUT1, one of the most abundant isoforms, displayed the greatest response to ethylene treatment. In clone PB217, ethylene treatment led to a higher accumulation of HbSUT1B in latex cells than in the inner bark tissues. Conversely, stronger expression of HbSUT1B was observed in inner bark tissues than in latex cells of PB260. A positive correlation with HbSUT1B transcript accumulation and increased latex production was further supported by its lower expression in latex cells of the virgin clone PB217.
巴西橡胶树是一种重要的工业作物，用于生产天然橡胶。胶乳生物合成发生在高度特化的胶乳细胞的细胞质中，需要蔗糖作为唯一的前体。乙烯刺激胶乳的产生导致高糖从内树皮的周围细胞流向胶乳细胞。本工作的目的是了解七个蔗糖转运蛋白（HbSUTs）和一个己糖转运蛋白（HbHXT1）在这个过程中的作用。使用了两个橡胶树克隆体：PB217 和 PB260，分别被描述为高产量和低产量的克隆体。这些糖转运蛋白（HbSUTs 和 HbHXT1）的表达模式在不同的生理条件下进行监测，发现它们在胶乳细胞中表达最多。其中一种丰度最高的同工酶 HbSUT1 对乙烯处理的反应最大。在 PB217 克隆体中，乙烯处理导致 HbSUT1B 在胶乳细胞中的积累高于内树皮组织。相反，在 PB260 中，内树皮组织中 HbSUT1B 的表达更强。其在处女克隆 PB217 的胶乳细胞中表达较低，进一步支持了与 HbSUT1B 转录物积累和增加的胶乳产量呈正相关。
